Electrical system



DC 1, 1931. w. E.' HOLLAND ET AL 1,834,778

ELECTRICAL SYSTEM Filed May 25, 1927 l*Patented Dec. 1, 19.31`r` 'y'iiNiTEn-, ST.ATES

A' PATENT oFFicE WALTEPIE'PIOELAND IWILLIAMH. GEIMDITCIL- or PHILADELPHIA, yPENNSYL- vANIA, kAssieNoias To PHILADELPHIA STORAGE' BATTERY COMPANY, or PHILA-f snEIiPHIA, PENNSYLVANIA, Ay lcoEPoEATIoN or PENNSYLVANIA ELECTETCAI. SYSTEM g rf"'Apiiim'anon med Nay 2e, 1927.` `seriali No. 194,401.

, Our invention; relates to electrical systems, and it liasp'articular,relation-to systems of control, such, for example, as ,are to vacuum-tube circuits.

:"5 ln lits broad aspect, one object ofy curin- `devices ccrtainfeatures are ca able, of en.`

ventionis tol provide voltage-'regulatingv means forl anrelectrical system, wherein a fr single manual controlsimultaneously adjusts :the voltageat a plurality of v.points in said `systeinzf ,'f

moie speciiic object of our invention is to provide means wherebyy the .voltage and cuii'eiitavail'ahle at the output terminals of ya currentsupply device may be varied to3` L values suitable for diferent loads, such, for

exam-ple, asithe audio-frequency amplifier,

.radio-frequency amplifierand detector plate f circuit loads present in a radio system.

Anotherobject of our invention isyto pro- La vide in a. radio current-supply device having.

- a plurality of positive direct-current output 'terminals and a common negative` terminal, a resistor network having a' ,single ad]ustable lresistor adapted to vary Lsimultaneously the yvoltages- -iniiials n y Although the primary 4object ofK our in-v a E, vacuum-tube `,receiving `system .vcntion is to provide a resistor network for .the yvoltage :regulation of radio y'power-supply eral applicatioinas will be brought out more fully inthe accompanying description, claim j fand drawings, wherein modification;

l Referring to F ig. vset ofirectifying units orcells, 2, 3, 4 and 5,

' Fig. 2 is asimilar view, but illustrating a cathode of cell 4 are connected by a conduc' t'or 9,*vvhilethe anodes of the cells 4 and 5 are.

., terminal 24 of the' transformer secondary connected by a conductor 11. l

applicable at two or morefofvthepositive tcr- Fig., 1nis a diagrammatic view of circuits and apparatus embodying my invention; an d.

1, a. rectifier 1 comprises a y jWhi'chima-y be of any .well-known type, such,

=inductive reactor 34.

current supply circuit (notshown) c Thecircuit 12 may include a transformercgg, 15 comprising a primary Winding 16 and a secondary Winding 17. The transformer, however, may have a single Winding only, if

desired, asin an auto-transformer. The ter.-

`minals of the primary rWinding 16V are con-figo nected by conductors 18 .and 19 through va switch'21 to the plug 14, thuscompletinga transformer rprimary circuit 22.

- The secondary Winding 17 is provided with terminals 23 and 24, the terminal 23 being-F65 connected by conductors 25 and 26 to the anode of cell 2 and the cathode of` cell 5.

' yllhclterininal 24 is connected by a conductor 27`and the conductor 9 to the anode of the cell Band the cathode of cell 4 fm lThe circuit 13 extendingrfrom Vthe rectifiery 1y comprises main positive and negative conductors 28 and 29 which :respectively extend Vtrom the conductors 8k and 11 to positive and negative' direct-current output terminals 31C .175 and 32. These terminals may represent the positivev and negative circuit connections( for not shown), though itis apparent that other load circuits may be connected insteadaso should it be desirable to employ the powerf supply device for a purpose other than radio. The pulsation inthe rectified currents traversing the output conductors 28 and' 29 may be smoothed out by means of lter appa-H85 Vvratus 33, comprising an inductive reactor 34,

which is serially included in the positive conductor 28 and capacitive reactors 35 and36 `which arey connected in shunt relation tothe output" circuit 13 on opposite sides of theV` 90 y When the plug. 14 is electrically connected tothealternating current supply circuit (not f shown), alternating currents traverse the vprimary circuit `22 and, asa result, alternat-j ing potentials are established in the secondary Winding 17 of the transformer 15. `Assuming that at any particular instant the Winding 17 is positive and the terminal 23100 negative, then currents flow from the transformer winding 17 through the conductor 27, the conductor 9, the cell 3, the conductor 8,

the positive conductor 28, the choke coil 84V and the conductor 28a to positive terminal connection 31. From here the currents may pass through, say, the plate circuit of a power amplifier tube (not shown) to the negative terminal connection 32. The current next flows from the terminal 32 through the negative conductor 29, the conductor 11, the cell 5, the conductor 26 and the conductor 25 to the transformer secondary winding 17.

When the polarity of the transformer secondary winding 17 reverses, then currents pass from the secondary terminal 23 through the conductor 25, the cell 2, the conductor 28, vthe cholecoil 34 and the conductor 28a to the amplifier apparatus (not shown) asso` ciated with the terminal connections 31 and 32, the negative conductor 29, the cell 4 and the conductor 27, to the transformer secondary winding 17. Thus both half lwaves of the alternating-current cycle are rectified and theoutput terminals 31 and 32 are supplied with 'a substantially constant directcurrent potential.

In accordance with our invention, addiltional direct-current output .terminals 37 and v38 are provided in the event that the currentsupply device Ais associated with a vacuumtube system (not shown) employing, say, amplifier and detector circuits requiring reduced plate voltages,'our invention, in

particular, contemplating the use of a resistor network 39 characterized by the fact that a single adjustment effects a simultaneous variation in the voltages-at at least two of the direct-current terminals 31, 37 and 38.

To this end, we provide a variable resistor 41 and a `fixed yresistor 42. One terminal 43 ofthe resistor 41 isconnec-ted to the positive conductor 28a` andV direct-current terminal 31. Anopposite terminal 44is connected by a conductor 45 to an adjacent terminal 46 of the fixed resistor 42.

The direct-current terminal 37 is connected by conductor 47 to the conductor 45, so that the variable resistor 41 is connected in shunt relation to the positive direct-current terminals 31 and 37. The resistor 41, however, isconnected in series 'relation with the fixed resistor `42. A remaining terminal 48 of the fixed resistor 42 is connected bya conductor 49 yto 'the direct-current terminal 38. The relative resistance values 'of the resistors 41 and 42 are preferably such that the adjustment of theyariable rresistor 41v causes a large variation in the voltage or power delivered to the terminal 37 and a simultaneous but smaller variation at the terminal 38.

The variable resistor 41 may be connected 'to the negative conductor 29 through a capacitive reactor 51 which affords a high impedance to the direct currents traversing the output circuit 18 but a relatively low impedance to alternating currents. Thus a slight filtering effect is established which is supplemental to that of the filter apparatus Inasmuch as the capacitive reactor 51 is conneeted in shunt relation to the output terminals 37 and 32, a low impedance path is afforded such alternating or fluctuating currents as are established in the circuits connected to the said output terminals. y

A further connection to the negative conductor 29 is afforded by means of a capacitive reactor 52 which extends from the terminal connection 38 and the resistor 42 to the negative conductor 29. The capacitive reactor 52alsoserves as a lowimpedance path for alternatingcurrents established in the external-circuit (not shown.) connected lto the terminal connections 38 and'32, but a high impedance path to direct currents.

In operation, assuming that load circuits are connected to the pairs of terminals, 31- 32, 237-32, and 38-32, respectively, which require predetermined high, medium and loW voltages, and that the plug 14 is electrically connected to an alternating current supply circuit (not shown), the variable resistor 41 isadjusted until thefdesi'red voltage and power requirements at the pairs of terminals whose voltages are controllable are established. It is noted that such regulation involves the adjustment of one resistor only. Vhen used with a radio receiving set, the regulation can be accomplished by anyone by means of the ear and without using meters. This greatly simplifies what has heretoforebeen an exceedingly uncertain process.

Fig. 2 illustrates diagrammatically a eurrent-supply system operating directly from a. source of direct-current energy (not shown), the system being distinguishable irom Fig. 1 in the absence of the transformer 15 and the rectifier 1. The vresistor network 39 is also slightly modified in the fact that a Vthird fixed resistor 53 is connected in shunt relation to the capacitive reactor 52 and across the low voltage terminals 38 and 32. The operation of this resistor network, however, is otherwise described in connection with Fig. 1.

Vhile we have shown only two embodiments of our invention, for the purpose of describing the same and illustrating their principles of construction and operation, it is apparent that various changes and modifications may be made therein, without departing from the spirit of our invention, and We desire, therefore, that only such limitations shall be imposed thereon, as are indicated in theappended claim or as are demanded by the prior art.

We claim :l i Y In an electrical power supply system for radio receiving systems, the combination of a source of uni-directional current having a [iii plurality of positive output terminals and a negative terminal for supplying potentials to the ampliiier and detector stages of said receiving systems and means for simultane-` ously adjusting said potentials comprising a variable resistance connected between the terfrom one of the amplifier terminals to saidy negative terminal and another condenser connected from the detector terminal to said negative terminal for substantially reducing any variations 1n said un1d1rectional current which may be present and to provide a low impedance return for the signal currents of said receiving systems.

WALTER E. HOLLAND. WILLIAM H. GRIMDITCH. 

